Attachment-plug.



E. G. K. ANDERSON.

AHACHMENT PLUG.

APPLICATION men APR.10. |913.

l 1,225,391 Patented May 8,1917.

UNITED sTATEs PATENT oEEICE.

EIRN'SL G'. IK. ANDERSON, OF CHICAGO, ILLINOIS,VA SSIGNOR T0 BENJAMINELECTRIC MANUFACTURING COMPANY.

ATTACHMENTPLUG.

Specication of Letters Patent.

Patented May 8, 1917.

. to the accompanying drawing, forming a part of this speciiication.

My invention pertains to attachment plugs, and especially relates to theclass of plugs own as separable, .Ve., plugs consisting of two readilydisengageable members,.an outer member and. an inner member, of whichthe outer member is adapted to be inserted into a lamp socket or thelike, and the inner member carries binding terlminals for receiving theends of leading-in conductors. It is one of the principal objects of myinvention to provide a separable plug of a simple, convenient andeiiic1ent construction, in which the threaded contact of the outermember will be rotatable with respect to the remainder` thereof.

An attachment plug constructed in accordance with my invention isdescribed,

by way of example, in the following speci cation and shown in theaccompanying drawing. The construction shown and described, is, however,only one of those in which my invention may be embodied; and changesmaybe made therein without exceeding the scope of my invention asdefined in the appended claim:

In the drawing Figure 1 isan elevation of the plug; y

Fig. 2 is a section taken vertically through the same;

IFig'. 3 is a detached side view of the iniier contact sleeve of theouter plug mem- Fig. 4 is an inverted plan of the same;

Fig. 5 is' a vertical section through the insulating button of the innermember;

Fig. 6 is a view similar to Fig. 5, the section being taken, however, atright angles to that of Fig. 5; and

Fig. 7 is a detached inverted plan of the insulating button of the outerplug member.

Like reference characters refer to likeI parts throughout the followingspecification and the several figures of the aecompanying drawing.

As has been said, the plug consists of an outer member adapted to besecured into a wallsocket lamp socket or the like, and an inner member,adapted to make electrical connections with the outer member, and carrying binding terminals for receiving leading-in-wires. The outer membercomprises an insulating button 10 having an axial passage formedtherethrough, through which passes a rivet- 1.1, the outer end of whichis iianged, at 12, to form the outer center contact of the outer plugportion. The inner end of the rivet 11 is flanged over, at 13, andserves to secure in place the Seat portion 14: of a V shaped metallicstrip, the end 15 of which forms the inner.` center contact of the outerplug portion. iIhe strip 14, 15 is flexible and is reinforced by aspiral spring 16 disposed between the end 15 and the rivet 11, thebutton 10 being formed with a recess 17 for accommodating this spring.The button 10 is reduced at 18 to receive a metallic sleeve 19, which issecured in place thereon by means of tongues 20 which are lstamped outof the sleeve 19 and project into recesses 21 in the button. It will beseen that the sleeve 19 may be passed over the reduced portion of thebutton, the tongues 20 springing out to permit this. When, however, thetongues 20 have entered the recesses 21, the sleeve cannot be removedagain. The sleeve 19 is formed with an out wardly extending flange 22 atits outer end, which flange engages against the shoulder -formed byreducing the portion 18 at the button.

Rotatably mounted on the sleeve 19, so as to make electrical connectiontherewith, is the threaded contact 23 of the outer plug portion. Thethreaded contact passes through, and is fianged over beyond, aninsulating thumb ring 24 by means of which the contact may bemanipulated in screwing the plug into or out of a socket. The sleeve 19is formed with a Hange 25, at its inner end, which engages against theinner end of the threaded contact 23, and thus prevents the latter frombeing withdrawn lengthiwise, while permitting it to rotate freely withrespect to the sleeve 19.

The sleeve 19 is formed with a plurality of slots 26 extending from itsinner edge outward, whereby a certain resiliency, in a radial direction,1s given. The sleeve is fur ther formed with an inwardly extendingcircumferential bead 27, which, when the inner plug member is in placein the outer plug member, is engaged by a corresponding circumferentialgroove 28 formed in a sleeve Contact 29, @which forms part-of the innerplug member. The sleeve contact 29 is formed with 'a reduced andscrewthreaded collar 30fat its inner end; and it carries, at its outerend, an insulating button 3l. This button rests upon the shoulder formedby the reduced collar 30 and is retained in place by the upper edge ofthe sleeve contact 29, which is spun inward somewhat, to that end. Thebutton 31 is of a substantially hemispherical shape at its upper partand enters a .correspondingly shaped cavity 32- formed inthe inner 'faceof the button 1.0I of the outer plug member, so that thecentercontactofth'e inner plug member, to bedescribed below, canengage thecenter contact 15 of the outer plug member. A-

The button 31 of.l the inner plugmember is formed, at the center of.itsupperpartf with a cavity 33 having two holes 34 communicatingtherewith and with the lower end of the button... -In the cavity 33 liesabinding terminal plate 35 having lugs A36- which are bent downward topassthrough theholes 34, these lugs being bent over at their ends so asto retain the plate 35 in position. The plate 35 has a screw threadedhole through which passes a screw 37, which also passes throughVadished. center contact- 38. Communicatmg with the chamber 3 3, is apassage 39, through which a lead conductor may be brought to the plate35 and looped around the screw `37, in which position it may be'secured,lbeneath the center contact 38, by tightening the screw 37 Theinsulating button 31 is formed with acavity 39 at 'one side thereof,into which cavity the metal ofthe sleeve contact 29 is bent, so as toform a square recess 40 in the sleeve contact. The cavity 39 is largerthan the bent-in portion of the sleeve contact 29, so as to provide roomfor the passage of the lead conductor behind the sleeve contact 29 andover the outer edge of the same. A square nut 41 is placed in the recess40, and receives a' binding screw 42. The second lead wire is passed upinto the cavity 39, behind the sleeve contact 29, and 'is bent over thelatter and secured beneath the binding screw 42 (Fig. i6). It will beseen, therefore, that one of the leading-in conductors is in electricalconnection with the central contact 38, while the other leading-inconductor is in electrical connection with the sleevecontact 29. l

An insulating bushing is: threaded into the collar 30, and is of suchlength that its edge will bind againsttherlead conductors and force themagainst the button 31, when the bushing is screwed home into the collar30. By this means, a conductor grip is provided,

-translating 'device Which is connected to the which prevents theleading-in conductors from being torn away from the binding terminalsduring the use of the device or 111 case of a sudden pull being impartedto the reducing the collar 30 of the sleeve contact 29.

In the use of the device, the outer member is-secured into a Wallsocket, lamp socket or the like, it being noted that, by reason of the'fact that the button 10 can remain stationarywith respect to thethreaded sleeve 23, the latter rotating uponthe button, the outer memberwill be Accidental loosenin thusj is prevented. enever it is desired toco'upleup a sadiron, electric fan', or other conductors of the innermember, this is effected by simply pushing the inner member into theouter member. When isjdone, the center contact38 of the inner membermakes connection with the center contact 15 of theouter member, thelatter being held in contact by reason of its own resiliency aidedby'that of the spring 16. The sleeve contact 29 makes electrical-connection with the sleeve 19 of the outer member, its groove 28engaging inthe bead 27 of the sleeve 19 and serving to secure. the innermember detachably in position. All that is necessary,

when the inner member is to .be withdrawn, is to exercise a pull upon itsufficient to overcome the spring actlon of the sleeve l19. The button31 of the inner member, and the sleeve contact 29 are so 'shaped thatthe members of the plug will come apart regardless of the direction inwhich a pull is ap'- plied to the inner member. For instance, if' theconductors are pulled upon in a direction at an angle to the. axis ofthe plug, the inner member will simply be withdrawn. This is ofconsiderable importance, in that in case of any accident, such as thefalling of a sadiron or the like, by which a sudden pull is imparted tothe conductors, the only result will be that the members of the plugwill be separated. By this means, injury to the plug itself or to theparts of the socket, is

avolded.

In separable plugs, as hertofore provided, it was inconvenient to'securethe plugs into the socket unless the parts of the plug wereseparatedfirst, since, in screwing 1n the plug, the conductor wiresbecame twisted. In the plug described above, this is not the case, therotatable threaded contact 28 perrmly locked in the socket. v of theouter member respert to the socket, the threaded Contact lwing rotatedalone to eil'ect the insertion of the plug. The plug is simple; and theparts are of such a nature that they may be made by Simple stamping andSpinning operations, wl'ufreby a strong and durable plug may be producedat a low cost.

What I claim as new and desire to secure by Letters Patent is:

.I separable attachment plug comprising two members, one of Said membersincluding an insulating base, electrically connected inner and outercenter contacts carried by said hase, a conducting sleeve secured tosaid basefnnd extending rearwardly thereof so as to form a chamber, anda threaded outer Contact rotatably mounted on said sleeve1 and the othermember including an insulating base having a center Contact forengagement with said inner center Contact and having an outer contactfor engagement with said sleeve, said members having interengagingmanually releasable means for retaining them together.

In Witness whereof, I have hereunto subscribed my name in the presenceof two Witnesses.

ERNST e. K. ANDERSON.

Witnesses: i

CHARLES G. COPE, T. L. ToBIAs.

Corrections in Letters Patent No. 1.225.391.

It ia hereby certified that in Letters Patent No. 1,225,391, granted Muy8, 1917,

upon the application of Ernst. G. K. Anderson, of Chicago, Iilinois, fornn improvement` in Attachment-Plugs," errors appear in the printedspecification requiring r correction ns follows: Page 2, line 35, "ortho reference-numeral 39 read 39,

emma page, line. 4l, for the recren-numeral 39 read 3.9"; and that thesaid Letrs Patent should be rend with these corrections therein that theacme may ccnform to tha record o! the case in the Pstent Office.

Signed and sealed this 17th day of July, A. D., i917.

F. W. H. CLAY,

[SEAL] Acting Commission# of Patna. (Il. J73-343.

